Units
What are the units for energy?
Joules
What must be conserved whenever it is transferred?
Energy
What two things are needed for work to occur?
A force must move an object in the direction of the force.
A machine does 200 J of work in 10 seconds. What is the power output of the machine?
20 W
What is the formula for calculating power?
What is work divided by time?
What are the units for power?
Watts
What is energy transferred per unit time?
Power
A student pushes a wall, but it does not move. How much work is done on the wall?
A person pushes a cart with a force of 160 N over 2 m in 4 seconds. What power is expended?
80 W
To lift a 40 N crate 5 m takes 20 seconds using a constant upward force. Calculate the power used.
10 W
What are the units for work?
Joules
What is force exerted over a distance?
Work
What is the ability to do work or cause change?
What is energy?
A machine produces 10 W of power for 5 seconds. How much work is done?
Work= Power X Time
What is 50 Joules?
A runner does 300 J of work in 5 seconds. What is the power?
What is 60 Watts?
What are the SI units for distance?
Meters
What is the transfer of energy?
Work
What is the rate at which work is done or energy is transferred?
What is power?
A student pushes a box with a force of 20 N over a distance of 4 m in the direction of the force. How much work is done on the box?
80 J
A student does 400 J of work in 8 seconds. What is the power?
What is 50 Watts?
What are the units for force?
Newtons
What is the ability to do work?
Energy
Two machines do the same amount of work. Machine A takes 4 seconds, and Machine B takes 8 seconds. Which has greater power?
Machine A, because it does the work in less time.
A weightlifter does 800 J of work lifting a 200 N barbell. How far did the barbell move upward during the lift?
4 m
A machine does 200 J of work in 20 seconds. What is its power?
What is 10 W?